Dirt roads seem to be disappearing, even in the fast-dwindling rural corners of Ramsey and Washington counties.
Having grown up alongside one, there's something about them that calls home to mind when traveling along the rolling hills and cornfields that make the freeways, malls and housing tracts seem remote.
So I was surprised to learn that there is such a thing as the Road Dust Institute, an organization begun by the Federal Highway Administration and a group of academics to examine issues involving dirt roads — and there are a lot of issues that bear examining. The institute, along with the Transportation Engineering and Road Research Alliance, has been holding a joint conference this week in Minneapolis.
It's a chance for those involved with finding ways to improve how we build safer and better roads to showcase and share their work, which includes research from our own Minnesota Department of Transportation (MnDOT).
MnDOT researchers Thomas Wood, Eddie Johnson and Melissa Cole have offered an idea that may ease two problems: road dust and shingle waste.
Minnesota generates more than 200,000 tons of shingle waste each year. Some, about 5 percent, is recycled into hot-mix asphalt pavement mixtures, but there is still a lot of waste left over. They looked at using ground-up shingles for surfacing and holding down dust on dirt roads after testing it last summer.
Their conclusions: It works dandy for reducing the "washboarding" of dirt roads and also reduces dust. Using shingle waste should be encouraged, even as more testing is done.
It's kind of a big deal. More than half of the nation's roadways are made of dirt, and road dust is more than a mere annoyance. Road dust also has adverse effects on air quality and crop yields and can reduce safety. In Western states, it's been found to contain a cancer-causing mineral called erionite.
